An ambitious, multidisciplinary project led by Amanda Sierra and Juan Manuel Encinas, Ikerbasque from the Achucarro centre (Achucarro Basque Center for Neuroscience) has discovered that epilepsy in a mouse model system reduces the production of new cells in the brain.
The hippocampus is a region of the brain involved in learning and memory and it is also the site of a robust neural stem cell population that generates new neurons. These hippocampal neural stem cells generate new neurons throughout the adult life of mammals. The cells generated by the hippocampal neural stem cells function in certain types of learning and memory and in responses to anxiety and stress.
This new research by Sierra and Encinas has revealed that in epileptic mice, hippocampal neural stem cells stop generating new neurons and are turn into reactive astrocytes. Reactive astrocytes promote inflammation and alter communication between neurons. Could manipulation of neural stem cells provide new ways to treat epilepsy?
This work has recently been published in the journal Cell Stem Cell.
The results of this research also confirms previous work by the same group that showed that epilepsy, which causes hyperexcitation of neurons but does not cause convulsions, activates neural stem cells, which leads to their premature exhaustion. Thus the generation of new neurons in the hippocampus ends is chronically reduced.
Juan Manuel Encinas, the leader of this study, highlighted the fact that “this discovery has enabled us to gain a better understanding about how neural stem cells function. We have shown that in addition to generating neurons and astrocytes, neural stem cells in the adult hippocampus can generate reactive astrocytes following an epileptic seizure.”
Encinas and his colleagues carried out this work in experimental animals that were genetically engineered to be epileptic. However, this discovery has clear implications in clinical practice and in the quest to develop new therapies for epilepsy, since the generation of new neurons (neurogenesis) is a process that is negatively affected in epileptic seizures in the hippocampus. Encinas pointed out, “If we can manage to preserve the population of neural stem cells and their capacity to generate new neurons in humans, it may be possible to prevent the development of certain symptoms associated with epilepsy and very likely to mitigate the damage that is caused in the hippocampus.”
In this project, Encinas and his colleagues collaborated with research groups attached to institutions such as the Baylor College of Medicine in Houston (United States), the Université Catholique de Louvain (Belgium), the Achucarro centre itself, and the UPV/EHU’s Genetic Expression Service.